The literature is replete with descriptions of surgical devices. Applicant's co-pending U.S. patent application Ser. No. 09/887,789 (now U.S. Pat. No. 7,032,798) lists some of these surgical devices, such as U.S. Pat. No. 4,705,038 to Sjostrom et al; U.S. Pat. No. 4,995,877 to Ams et al; U.S. Pat. No. 5,249,583 to Mallaby; U.S. Pat. No. 5,383,880 to Hooven; U.S. Pat. No. 5,395,033 to Byrne et al; U.S. Pat. No. 5,467,911 to Tsuruta et al; U.S. Pat. Nos. 5,518,163, 5,518,164 and 5,667,517, all to Hooven; U.S. Pat. No. 5,653,374 to Young et al.; U.S. Pat. No. 5,779,130 to Alesi et al.; and U.S. Pat. No. 5,954,259 to Viola et al.
One type of surgical device is a linear clamping, cutting and stapling device. An example of such a device is shown and described in U.S. Pat. No. 6,264,087 issued on Jul. 24, 2001. Such a device may be employed in a surgical procedure to resect a cancerous or anomalous tissue from a gastro-intestinal tract.
With respect to the structural features of the conventional linear clamping, cutting and stapling instrument which is shown in FIG. 1, the device includes a pistol grip-styled structure having an elongated shaft and distal portion. The distal portion includes a pair of scissors-styled gripping elements, which clamp the open ends of the colon closed. In this device, one of the two scissors-styled gripping elements, the anvil portion, moves or pivots relative to overall structure, whereas the other gripping element remains fixed relative to the overall structure. The actuation of this scissoring device (the pivoting of the anvil portion) is controlled by a grip trigger maintained in the handle.
In addition to the scissoring device, the distal portion also includes a stapling mechanism. The fixed gripping element of the scissoring mechanism includes a staple cartridge receiving region and a mechanism for driving the staples up through the clamped end of the tissue, against the anvil portion, thereby sealing the previously opened end. The scissoring elements may be integrally formed with the shaft or may be detachable such that various scissoring and stapling elements may be interchangeable.
One problem with the foregoing surgical devices, and in particular with the foregoing linear clamping, cutting and stapling devices such as that illustrated in FIG. 1, is the tendency of the opposing jaws of the clamping mechanism to be urged apart during the operation of cutting and stapling the tissue. Another problem with the foregoing surgical devices, and in particular with the foregoing linear clamping, cutting and stapling devices such as that illustrated in FIG. 1, is that the devices are difficult to maneuver. Because a linear clamping, cutting and stapling device may be employed corporeally, e.g., inside the body of a patient, the device must be small enough to be maneuvered inside the body of a patient. Conventional linear clamping, cutting and stapling devices such as that illustrated in FIG. 1 have an overall length which increases the difficulty in maneuvering the device, especially inside the patient's body.
Still another problem with the foregoing surgical devices, and in particular with the foregoing linear clamping, cutting and stapling devices such as that illustrated in FIG. 1, is that the torque required to cut and staple a section of tissue is undesirably high, thereby causing stress in various components of the devices. For instance, in other linear clamping, cutting and stapling devices which move scissoring and stapling elements from the proximal end to the distal end, a high torque is required to move the scissoring and stapling elements when the scissoring and stapling elements are at the distal end. Thus, when the cutting and stapling element has traveled to the distal end of the jaws, the high torque causes stress in the scissoring and stapling elements, and driver mechanisms of the device.